Fix health check from Google's Load Balancer

This change adds 2 options for windows:
--forward-healthcheck-vip: If true forward service VIP for health check
port
--root-hnsendpoint-name: The name of the hns endpoint name for root
namespace attached to l2bridge, default is cbr0

When --forward-healthcheck-vip is set as true and winkernel is used,
kube-proxy will add an hns load balancer to forward health check request
that was sent to lb_vip:healthcheck_port to the node_ip:healthcheck_port.
Without this forwarding, the health check from google load balancer will
fail, and it will stop forwarding traffic to the windows node.

This change fixes the following 2 cases for service:
- `externalTrafficPolicy: Cluster` (default option): healthcheck_port is
10256 for all services. Without this fix, all traffic won't be directly
forwarded to windows node. It will always go through a linux node and
get forwarded to windows from there.
- `externalTrafficPolicy: Local`: different healthcheck_port for each
service that is configured as local. Without this fix, this feature
won't work on windows node at all. This feature preserves client ip
that tries to connect to their application running in windows pod.

Change-Id: If4513e72900101ef70d86b91155e56a1f8c79719

cluster/gce/windows/k8s-node-setup.psm1

@@ -892,8 +892,12 @@ function Configure-HostNetworkingService {
         -Verbose
     $created_hns_network = $true
   }
-
+  # This name of endpoint is referred in pkg/proxy/winkernel/proxier.go as part of
+  # kube-proxy as well. A health check port for every service that is specified as
+  # "externalTrafficPolicy: local" will be added on the endpoint.
+  # PLEASE KEEP THEM CONSISTENT!!!
   $endpoint_name = "cbr0"
+
   $vnic_name = "vEthernet (${endpoint_name})"
 
   $hns_endpoint = Get-HnsEndpoint | Where-Object Name -eq $endpoint_name

cmd/kube-proxy/app/init_windows.go

@@ -41,4 +41,6 @@ func (o *Options) addOSFlags(fs *pflag.FlagSet) {
 	fs.StringVar(&o.config.Winkernel.SourceVip, "source-vip", o.config.Winkernel.SourceVip, "The IP address of the source VIP for non-DSR.")
 	fs.StringVar(&o.config.Winkernel.NetworkName, "network-name", o.config.Winkernel.NetworkName, "The name of the cluster network.")
 	fs.BoolVar(&o.config.Winkernel.EnableDSR, "enable-dsr", o.config.Winkernel.EnableDSR, "If true make kube-proxy apply DSR policies for service VIP")
+	fs.StringVar(&o.config.Winkernel.RootHnsEndpointName, "root-hnsendpoint-name", "cbr0", "The name of the hns endpoint name for root namespace attached to l2bridge")
+	fs.BoolVar(&o.config.Winkernel.ForwardHealthCheckVip, "forward-healthcheck-vip", o.config.Winkernel.ForwardHealthCheckVip, "If true forward service VIP for health check port")
 }

cmd/kube-proxy/app/server_windows.go

@@ -24,7 +24,9 @@ package app
 import (
 	"errors"
 	"fmt"
+	"net"
 	goruntime "runtime"
+	"strconv"
 
 	// Enable pprof HTTP handlers.
 	_ "net/http/pprof"
@@ -97,8 +99,11 @@ func newProxyServer(config *proxyconfigapi.KubeProxyConfiguration, cleanupAndExi
 	}
 
 	var healthzServer healthcheck.ProxierHealthUpdater
+	var healthzPort int
 	if len(config.HealthzBindAddress) > 0 {
 		healthzServer = healthcheck.NewProxierHealthServer(config.HealthzBindAddress, 2*config.IPTables.SyncPeriod.Duration, recorder, nodeRef)
+		_, port, _ := net.SplitHostPort(config.HealthzBindAddress)
+		healthzPort, _ = strconv.Atoi(port)
 	}
 
 	var proxier proxy.Provider
@@ -120,6 +125,7 @@ func newProxyServer(config *proxyconfigapi.KubeProxyConfiguration, cleanupAndExi
 				recorder,
 				healthzServer,
 				config.Winkernel,
+				healthzPort,
 			)
 		} else {
 
@@ -134,6 +140,7 @@ func newProxyServer(config *proxyconfigapi.KubeProxyConfiguration, cleanupAndExi
 				recorder,
 				healthzServer,
 				config.Winkernel,
+				healthzPort,
 			)
 
 		}

pkg/generated/openapi/zz_generated.openapi.go

@@ -49802,8 +49802,24 @@ func schema_k8sio_kube_proxy_config_v1alpha1_KubeProxyWinkernelConfiguration(ref
 							Format:      "",
 						},
 					},
+					"rootHnsEndpointName": {
+						SchemaProps: spec.SchemaProps{
+							Description: "RootHnsEndpointName is the name of hnsendpoint that is attached to l2bridge for root network namespace",
+							Default:     "",
+							Type:        []string{"string"},
+							Format:      "",
 						},
-				Required: []string{"networkName", "sourceVip", "enableDSR"},
+					},
+					"forwardHealthCheckVip": {
+						SchemaProps: spec.SchemaProps{
+							Description: "ForwardHealthCheckVip forwards service VIP for health check port on Windows",
+							Default:     false,
+							Type:        []string{"boolean"},
+							Format:      "",
+						},
+					},
+				},
+				Required: []string{"networkName", "sourceVip", "enableDSR", "rootHnsEndpointName", "forwardHealthCheckVip"},
 			},
 		},
 	}

pkg/proxy/apis/config/scheme/testdata/KubeProxyConfiguration/after/v1alpha1.yaml

@@ -42,5 +42,7 @@ showHiddenMetricsForVersion: ""
 udpIdleTimeout: 250ms
 winkernel:
   enableDSR: false
+  forwardHealthCheckVip: false
   networkName: ""
+  rootHnsEndpointName: ""
   sourceVip: ""

pkg/proxy/apis/config/scheme/testdata/KubeProxyConfiguration/roundtrip/default/v1alpha1.yaml

@@ -42,5 +42,7 @@ showHiddenMetricsForVersion: ""
 udpIdleTimeout: 250ms
 winkernel:
   enableDSR: false
+  forwardHealthCheckVip: false
   networkName: ""
+  rootHnsEndpointName: ""
   sourceVip: ""

pkg/proxy/apis/config/types.go

@@ -99,6 +99,12 @@ type KubeProxyWinkernelConfiguration struct {
 	// enableDSR tells kube-proxy whether HNS policies should be created
 	// with DSR
 	EnableDSR bool
+	// RootHnsEndpointName is the name of hnsendpoint that is attached to
+	// l2bridge for root network namespace
+	RootHnsEndpointName string
+	// ForwardHealthCheckVip forwards service VIP for health check port on
+	// Windows
+	ForwardHealthCheckVip bool
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

pkg/proxy/apis/config/v1alpha1/zz_generated.conversion.go

@@ -262,6 +262,8 @@ func autoConvert_v1alpha1_KubeProxyWinkernelConfiguration_To_config_KubeProxyWin
 	out.NetworkName = in.NetworkName
 	out.SourceVip = in.SourceVip
 	out.EnableDSR = in.EnableDSR
+	out.RootHnsEndpointName = in.RootHnsEndpointName
+	out.ForwardHealthCheckVip = in.ForwardHealthCheckVip
 	return nil
 }
 
@@ -274,6 +276,8 @@ func autoConvert_config_KubeProxyWinkernelConfiguration_To_v1alpha1_KubeProxyWin
 	out.NetworkName = in.NetworkName
 	out.SourceVip = in.SourceVip
 	out.EnableDSR = in.EnableDSR
+	out.RootHnsEndpointName = in.RootHnsEndpointName
+	out.ForwardHealthCheckVip = in.ForwardHealthCheckVip
 	return nil
 }
 

pkg/proxy/winkernel/hnsV1.go

@@ -33,6 +33,7 @@ type HostNetworkService interface {
 	getNetworkByName(name string) (*hnsNetworkInfo, error)
 	getEndpointByID(id string) (*endpointsInfo, error)
 	getEndpointByIpAddress(ip string, networkName string) (*endpointsInfo, error)
+	getEndpointByName(id string) (*endpointsInfo, error)
 	createEndpoint(ep *endpointsInfo, networkName string) (*endpointsInfo, error)
 	deleteEndpoint(hnsID string) error
 	getLoadBalancer(endpoints []endpointsInfo, flags loadBalancerFlags, sourceVip string, vip string, protocol uint16, internalPort uint16, externalPort uint16) (*loadBalancerInfo, error)
@@ -63,7 +64,8 @@ func (hns hnsV1) getEndpointByID(id string) (*endpointsInfo, error) {
 	}
 	return &endpointsInfo{
 		ip: hnsendpoint.IPAddress.String(),
-		isLocal:    !hnsendpoint.IsRemoteEndpoint, //TODO: Change isLocal to isRemote
+		//TODO: Change isLocal to isRemote
+		isLocal:    !hnsendpoint.IsRemoteEndpoint,
 		macAddress: hnsendpoint.MacAddress,
 		hnsID:      hnsendpoint.Id,
 		hns:        hns,
@@ -108,6 +110,23 @@ func (hns hnsV1) getEndpointByIpAddress(ip string, networkName string) (*endpoin
 
 	return nil, fmt.Errorf("Endpoint %v not found on network %s", ip, networkName)
 }
+
+func (hns hnsV1) getEndpointByName(name string) (*endpointsInfo, error) {
+	hnsendpoint, err := hcsshim.GetHNSEndpointByName(name)
+	if err != nil {
+		klog.ErrorS(err, "failed to get HNS endpoint by name", "name", name)
+		return nil, err
+	}
+	return &endpointsInfo{
+		ip: hnsendpoint.IPAddress.String(),
+		//TODO: Change isLocal to isRemote
+		isLocal:    !hnsendpoint.IsRemoteEndpoint,
+		macAddress: hnsendpoint.MacAddress,
+		hnsID:      hnsendpoint.Id,
+		hns:        hns,
+	}, nil
+}
+
 func (hns hnsV1) createEndpoint(ep *endpointsInfo, networkName string) (*endpointsInfo, error) {
 	hnsNetwork, err := hcsshim.GetHNSNetworkByName(networkName)
 	if err != nil {

pkg/proxy/winkernel/hnsV2.go

@@ -114,6 +114,19 @@ func (hns hnsV2) getEndpointByIpAddress(ip string, networkName string) (*endpoin
 
 	return nil, fmt.Errorf("Endpoint %v not found on network %s", ip, networkName)
 }
+func (hns hnsV2) getEndpointByName(name string) (*endpointsInfo, error) {
+	hnsendpoint, err := hcn.GetEndpointByName(name)
+	if err != nil {
+		return nil, err
+	}
+	return &endpointsInfo{ //TODO: fill out PA
+		ip:         hnsendpoint.IpConfigurations[0].IpAddress,
+		isLocal:    uint32(hnsendpoint.Flags&hcn.EndpointFlagsRemoteEndpoint) == 0, //TODO: Change isLocal to isRemote
+		macAddress: hnsendpoint.MacAddress,
+		hnsID:      hnsendpoint.Id,
+		hns:        hns,
+	}, nil
+}
 func (hns hnsV2) createEndpoint(ep *endpointsInfo, networkName string) (*endpointsInfo, error) {
 	hnsNetwork, err := hcn.GetNetworkByName(networkName)
 	if err != nil {

pkg/proxy/winkernel/hns_test.go

@@ -26,6 +26,8 @@ import (
 
 	"strings"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
 const (
@@ -56,12 +58,12 @@ func TestGetEndpointByID(t *testing.T) {
 	testGetEndpointByID(t, hnsV1)
 	testGetEndpointByID(t, hnsV2)
 }
-func TestGetEndpointByIpAddress(t *testing.T) {
+func TestGetEndpointByIpAddressAndName(t *testing.T) {
 	hnsV1 := hnsV1{}
 	hnsV2 := hnsV2{}
 
-	testGetEndpointByIpAddress(t, hnsV1)
-	testGetEndpointByIpAddress(t, hnsV2)
+	testGetEndpointByIpAddressAndName(t, hnsV1)
+	testGetEndpointByIpAddressAndName(t, hnsV2)
 }
 func TestCreateEndpointLocal(t *testing.T) {
 	hnsV1 := hnsV1{}
@@ -165,7 +167,7 @@ func testGetEndpointByID(t *testing.T, hns HostNetworkService) {
 		t.Error(err)
 	}
 }
-func testGetEndpointByIpAddress(t *testing.T, hns HostNetworkService) {
+func testGetEndpointByIpAddressAndName(t *testing.T, hns HostNetworkService) {
 	Network := mustTestNetwork(t)
 
 	ipConfig := &hcn.IpConfig{
@@ -195,6 +197,15 @@ func testGetEndpointByIpAddress(t *testing.T, hns HostNetworkService) {
 		t.Errorf("%v does not match %v", endpoint.ip, Endpoint.IpConfigurations[0].IpAddress)
 	}
 
+	endpoint, err = hns.getEndpointByName(Endpoint.Name)
+	if err != nil {
+		t.Error(err)
+	}
+	diff := cmp.Diff(endpoint, Endpoint)
+	if diff != "" {
+		t.Errorf("getEndpointByName(%s) returned a different endpoint. Diff: %s ", Endpoint.Name, diff)
+	}
+
 	err = Endpoint.Delete()
 	if err != nil {
 		t.Error(err)

pkg/proxy/winkernel/proxier.go

@@ -89,6 +89,7 @@ type externalIPInfo struct {
 type loadBalancerIngressInfo struct {
 	ip               string
 	hnsID            string
+	healthCheckHnsID string
 }
 
 type loadBalancerInfo struct {
@@ -548,6 +549,10 @@ type Proxier struct {
 	hostMac           string
 	isDSR             bool
 	supportedFeatures hcn.SupportedFeatures
+	healthzPort       int
+
+	forwardHealthCheckVip bool
+	rootHnsEndpointName   string
 }
 
 type localPort struct {
@@ -593,6 +598,7 @@ func NewProxier(
 	recorder events.EventRecorder,
 	healthzServer healthcheck.ProxierHealthUpdater,
 	config config.KubeProxyWinkernelConfiguration,
+	healthzPort int,
 ) (*Proxier, error) {
 	masqueradeValue := 1 << uint(masqueradeBit)
 	masqueradeMark := fmt.Sprintf("%#08x/%#08x", masqueradeValue, masqueradeValue)
@@ -702,6 +708,9 @@ func NewProxier(
 		isDSR:                 isDSR,
 		supportedFeatures:     supportedFeatures,
 		isIPv6Mode:            isIPv6,
+		healthzPort:           healthzPort,
+		rootHnsEndpointName:   config.RootHnsEndpointName,
+		forwardHealthCheckVip: config.ForwardHealthCheckVip,
 	}
 
 	ipFamily := v1.IPv4Protocol
@@ -730,18 +739,19 @@ func NewDualStackProxier(
 	recorder events.EventRecorder,
 	healthzServer healthcheck.ProxierHealthUpdater,
 	config config.KubeProxyWinkernelConfiguration,
+	healthzPort int,
 ) (proxy.Provider, error) {
 
 	// Create an ipv4 instance of the single-stack proxier
 	ipv4Proxier, err := NewProxier(syncPeriod, minSyncPeriod, masqueradeAll, masqueradeBit,
-		clusterCIDR, hostname, nodeIP[0], recorder, healthzServer, config)
+		clusterCIDR, hostname, nodeIP[0], recorder, healthzServer, config, healthzPort)
 
 	if err != nil {
 		return nil, fmt.Errorf("unable to create ipv4 proxier: %v, hostname: %s, clusterCIDR : %s, nodeIP:%v", err, hostname, clusterCIDR, nodeIP[0])
 	}
 
 	ipv6Proxier, err := NewProxier(syncPeriod, minSyncPeriod, masqueradeAll, masqueradeBit,
-		clusterCIDR, hostname, nodeIP[1], recorder, healthzServer, config)
+		clusterCIDR, hostname, nodeIP[1], recorder, healthzServer, config, healthzPort)
 	if err != nil {
 		return nil, fmt.Errorf("unable to create ipv6 proxier: %v, hostname: %s, clusterCIDR : %s, nodeIP:%v", err, hostname, clusterCIDR, nodeIP[1])
 	}
@@ -796,6 +806,10 @@ func (svcInfo *serviceInfo) deleteAllHnsLoadBalancerPolicy() {
 	for _, lbIngressIP := range svcInfo.loadBalancerIngressIPs {
 		hns.deleteLoadBalancer(lbIngressIP.hnsID)
 		lbIngressIP.hnsID = ""
+		if lbIngressIP.healthCheckHnsID != "" {
+			hns.deleteLoadBalancer(lbIngressIP.healthCheckHnsID)
+			lbIngressIP.healthCheckHnsID = ""
+		}
 	}
 }
 
@@ -988,6 +1002,11 @@ func (proxier *Proxier) syncProxyRules() {
 	hnsNetworkName := proxier.network.name
 	hns := proxier.hns
 
+	var gatewayHnsendpoint *endpointsInfo
+	if proxier.forwardHealthCheckVip {
+		gatewayHnsendpoint, _ = hns.getEndpointByName(proxier.rootHnsEndpointName)
+	}
+
 	prevNetworkID := proxier.network.id
 	updatedNetwork, err := hns.getNetworkByName(hnsNetworkName)
 	if updatedNetwork == nil || updatedNetwork.id != prevNetworkID || isNetworkNotFoundError(err) {
@@ -1319,7 +1338,30 @@ func (proxier *Proxier) syncProxyRules() {
 			} else {
 				klog.V(3).InfoS("Skipped creating Hns LoadBalancer for loadBalancer Ingress resources", "lbIngressIP", lbIngressIP)
 			}
+			lbIngressIP.hnsID = hnsLoadBalancer.hnsID
+			klog.V(3).InfoS("Hns LoadBalancer resource created for loadBalancer Ingress resources", "lbIngressIP", lbIngressIP)
 
+			if proxier.forwardHealthCheckVip && gatewayHnsendpoint != nil {
+				nodeport := proxier.healthzPort
+				if svcInfo.HealthCheckNodePort() != 0 {
+					nodeport = svcInfo.HealthCheckNodePort()
+				}
+				hnsHealthCheckLoadBalancer, err := hns.getLoadBalancer(
+					[]endpointsInfo{*gatewayHnsendpoint},
+					loadBalancerFlags{isDSR: false, useMUX: svcInfo.preserveDIP, preserveDIP: svcInfo.preserveDIP},
+					sourceVip,
+					lbIngressIP.ip,
+					Enum(svcInfo.Protocol()),
+					uint16(nodeport),
+					uint16(nodeport),
+				)
+				if err != nil {
+					klog.ErrorS(err, "Policy creation failed")
+					continue
+				}
+				lbIngressIP.healthCheckHnsID = hnsHealthCheckLoadBalancer.hnsID
+				klog.V(3).InfoS("Hns Health Check LoadBalancer resource created for loadBalancer Ingress resources", "ip", lbIngressIP)
+			}
 		}
 		svcInfo.policyApplied = true
 		klog.V(2).InfoS("Policy successfully applied for service", "serviceInfo", svcInfo)

pkg/proxy/winkernel/proxier_test.go

@@ -2,7 +2,7 @@
 // +build windows
 
 /*
-Copyright 2018 The Kubernetes Authors.
+Copyright 2021 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -73,6 +73,15 @@ func (hns fakeHNS) getEndpointByID(id string) (*endpointsInfo, error) {
 	return nil, nil
 }
 
+func (hns fakeHNS) getEndpointByName(name string) (*endpointsInfo, error) {
+	return &endpointsInfo{
+		isLocal:    true,
+		macAddress: macAddress,
+		hnsID:      guid,
+		hns:        hns,
+	}, nil
+}
+
 func (hns fakeHNS) getEndpointByIpAddress(ip string, networkName string) (*endpointsInfo, error) {
 	_, ipNet, _ := netutils.ParseCIDRSloppy(destinationPrefix)
 
@@ -699,7 +708,6 @@ func TestCreateLoadBalancer(t *testing.T) {
 			t.Errorf("%v does not match %v", svcInfo.hnsID, guid)
 		}
 	}
-
 }
 
 func TestCreateDsrLoadBalancer(t *testing.T) {
@@ -717,6 +725,7 @@ func TestCreateDsrLoadBalancer(t *testing.T) {
 		Port:           "p80",
 		Protocol:       v1.ProtocolTCP,
 	}
+	lbIP := "11.21.31.41"
 
 	makeServiceMap(proxier,
 		makeTestService(svcPortName.Namespace, svcPortName.Name, func(svc *v1.Service) {
@@ -729,6 +738,9 @@ func TestCreateDsrLoadBalancer(t *testing.T) {
 				Protocol: v1.ProtocolTCP,
 				NodePort: int32(svcNodePort),
 			}}
+			svc.Status.LoadBalancer.Ingress = []v1.LoadBalancerIngress{{
+				IP: lbIP,
+			}}
 		}),
 	)
 	tcpProtocol := v1.ProtocolTCP
@@ -761,6 +773,11 @@ func TestCreateDsrLoadBalancer(t *testing.T) {
 		if svcInfo.localTrafficDSR != true {
 			t.Errorf("Failed to create DSR loadbalancer with local traffic policy")
 		}
+		if len(svcInfo.loadBalancerIngressIPs) == 0 {
+			t.Errorf("svcInfo does not have any loadBalancerIngressIPs, %+v", svcInfo)
+		} else if svcInfo.loadBalancerIngressIPs[0].healthCheckHnsID != guid {
+			t.Errorf("The Hns Loadbalancer HealthCheck Id %v does not match %v. ServicePortName %q", svcInfo.loadBalancerIngressIPs[0].healthCheckHnsID, guid, svcPortName.String())
+		}
 	}
 }
 

staging/src/k8s.io/kube-proxy/config/v1alpha1/types.go

@@ -95,6 +95,12 @@ type KubeProxyWinkernelConfiguration struct {
 	// enableDSR tells kube-proxy whether HNS policies should be created
 	// with DSR
 	EnableDSR bool `json:"enableDSR"`
+	// RootHnsEndpointName is the name of hnsendpoint that is attached to
+	// l2bridge for root network namespace
+	RootHnsEndpointName string `json:"rootHnsEndpointName"`
+	// ForwardHealthCheckVip forwards service VIP for health check port on
+	// Windows
+	ForwardHealthCheckVip bool `json:"forwardHealthCheckVip"`
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object